Clamp-dog



A. P. MILLER.

CLAMP DOG.

APPLICATlON FILED APR. 13. 1920.

Patented Apr. 26, 192E.

BY ATTORPJEVS WITNESSES F 2 v V .UITED STATES- PATET QEFICE.

' CLAMP-DOG.

Application filed April 13, 1920. Serial No. 373,501.

To all whom it may concern Be it known that I, ALBERT PAUL MILLER, a citizen of the United States, and a resident of Newcastle, in the county of Henry and State of Indiana, have invented certain new and useful Improvements in Clamp-Dogs, of which the following is a specification.

My invention relates to an improved dog or driver and more particularly to an improved clamp dog especially adapted for use with grinders or lathes.

An important object of my invention is to provide an improved clamp dog or driven which is adjustable and otherwise So con-v structed and operated as to exert a powerful effective gripping action on the work to transmit the required rotation to the work without marring the surface of the same.

Another object of my invention isto provide an improved clamping dog or driver of simple and durable construction, easy and inexpensive to manufacture and reliable in operation.

Other objects and advantages reside in the certain novel features of the construction, arrangement and combination of parts and will become apparent as the description proceeds, reference being had to the accompanying drawings forming part of this specification and in which:

Figure 1 is a vertical section through my improvement, parts being shown in elevation for the sake of illustration, 7

Fig. 2 is a perspective view of my inprovement in clamping position. Referring to the drawings it Will be apparent my invention comprises a bed block 5 having a recess 6 extending entirely through the central portion thereof. The bed block is enlarged adjacent the recess to provide spaced vertical walls 7 as shown in the drawing. Near each end of the bed block there is provided a smooth bore 8 extending entirely therethrough.

A pivot pin 9 is fixed in the vertical walls 7 of the bed block and extends transversely across the recess between said spaced vertical walls. A clamping cam 10 having an operating lever 10' is mounted for rotary movement on the fixed pivot pin and a coil spring 11 has one end seated in said pin and the other end seated in said cam to force said cam to clamping position and to normally retain the same in this position.

A clamping block 12 having a V-shaped Specification of Letters Patent.

Patented Apr. 26,1921.

recess 13 centrally disposed thereof is adapted to cooperate with the clamping cam in the clamping of the work. Adjacent each end thereof the clamping block is provided with threaded bores 14 extending entirely therethrough and which are so arranged as to allne With the smooth bores of the bed block when the blocks are associated in operative relation. Clamping screws 15 having heads 15 are provided to effect adjustment of the clamping block with respect to the bed block and these screws have their threaded portions engaged with the threaded portions of the clamping block and have smooth portions contacting with the smooth walls of the bores of the bed block. The smooth portions of the clamping screws are provided with an annular recess or groove 16 which coiiperates with retaining pins 17 mounted in the bed block and projecting into said grooves to prevent displacement of the clamping screws from the bed block while allowing free rotary movement thereof.

In practice the work having been received in the V-shaped recess of the clamping block, the clamping block is adjusted with respect to the clamping lever carried by the bed block by rotation of the clamping screws which is effected by turning the hexagonal heads thereof. During this operation the clamping lever has been rotatedand moved in inoperative or non-clamping position against the action of the coil spring. When the cam is released the coil spring throws the same to clamping position and if necessary the action of the spring may be supplemented by pressure applied to the cam lever. After the clamping cam has once been set to gripping position the action of the coil spring is ample to maintain the same in said position particularly as the major stress between the clamping cam and the work tends to increase the gripping action and the spring has usually only to take care of minor stresses such as are createdby vibration, etc. An important feature of my invention resides in the arrangement whereby an, adequate gripping force is provided for imparting rotary motion to the work without marring the surface of the work. In this connection it is to be noted that the surface of the V-shaped recess and the surface of the gripping cam are smooth and will not serve to bite into the surface of the work or otherwise injure or mar the same and at the same time the gripping action is so powerful and effective as to constrain the Work to rotation.

I claim:

A clamping dog for grinders, lathes and V the like comprising a'bed block having a recess, a pivot pin fixed in said bed block and extending transversely across said recess, a clamping cam mounted for rotary movement on said pivot pin, a coil spring having 10 one end seated in said pivot pin and the other end seated in said clamping cam to force said clamping cam to gripping position a clamping block associated With said bed block and means for adjusting said 15 clamping block with respect to said bed block.

' ALBERT PAUL MILLER. 

